Excited states of deformable odd 157,159 Tb nuclei: Nonconservation of the angular momentum of external nucleon
- PDF / 881,489 Bytes
- 13 Pages / 612 x 792 pts (letter) Page_size
- 84 Downloads / 226 Views
NUCLEI Theory
Excited States of Deformable Odd 157,159Tb Nuclei: Nonconservation of the Angular Momentum of External Nucleon* Sh. Sharipov and M. J. Ermamatov** Institute of Nuclear Physics, Ulughbek, Uzbekistan Received March 25, 2008; in final form, June 6, 2008
Abstract—The previously developed rotationally single-particle and vibrational model of the triaxial deformable odd nuclei is extended to the case where the total angular momentum of an external nucleon is not conserved. The calculated ratios of the excitation energies of the 157,159 Tb nuclei are compared with the existing experimental data. The ratios of E2-transition probabilities and those of quadrupole moments of the above nuclei are calculated using parameters determined from the spectra of these nuclei. PACS numbers: 21.60.-n, 21.60.Ev, 21.10.Re DOI: 10.1134/S1063778809010037
1. INTRODUCTION
for the axially symmetrical core by the Frankfurt group [13–17]. Importance of a rotation–vibration interaction and its equivalence to the rigid-asymmetric-rotor model, especially for the ground state and γ band, have been established. A numerical treatment of a general collective Hamiltonian has been developed in [6, 18]. In recent years, these studies have received renewed interest because of analytically solvable potentials [19–21]. A new algebraic method is proposed in recent works by Rowe and his collaborators [22, 23]. This method can give the possibility of investigation by diagonalization of the general Hamiltonian [24]. An approximate analytic solvable potential in the γ variable with a minimum at γ = π/6 with correct boundary conditions is studied in [25], using a fixed moment of inertia. A nuclear rotationally single-particle and vibrational model based on the Hamiltonian of [8] has been developed in [26–29]. Deformable odd nuclei with small triaxiality [26, 27] and deformable triaxial odd nuclei [28, 29] have been studied separately in these works. In both cases, there are no close states with different orbital momenta and spin–orbit coupling is strong and angular momentum of the external nucleon is approximately conserved. Spins and parities of the ground states of the nuclei have been taken to be equal to the spin of the external nucleon. However, if the external nucleon moves in the nonspherical field of the core, neither total angular momentum nor its projection on to any nuclear direction can be conserved and spins and parities of the ground states of nuclei should follow from the calculations and depend on the set of parameters occurring in this case.
It is well known that short- and long-range interactions exist between nucleons in nuclei. For medium and heavy nuclei, the strong short-range interaction leads to the assumption of a nuclear surface which can perform oscillations. This interaction gives a spherical form to the nuclei. The long-range interaction is connected to the self-consistent field which is described by the shell-model potential. Nucleons which are outside a closed shell cause a deviation from the spherical symmetry [1]. The m
Data Loading...
